The first thing you should know is that this is an equation of the form:
y (t) = Asen (wt)
Where,
w: angular speed
By definition,
w = 2 * pi * f
Where,
f: frequency
Substituting values:
3520 * pi = 2 * pi * f
Clearing f:
f = (3520 * pi) / (2 * pi)
f = 1760 hz
Answer:
f = 1760 hz
option 3